We present a novel DC motor driven soft robotic fish and optimization based on experimental, numerical and theoretical investigation into oscillating propulsion for primarily speed and secondarily efficiency. Our system outperforms the previously fastest soft robotic fish Zhong et al. 2017 by a significant margin of 27%, with speeds up to 0.85m/s. A simple wire-driven active body and soft compliant body were used to mimic highly efficient thunniform swimming. The efficient DC motor to drive the system decreases internal losses compared to other soft robotic oscillating propulsion systems which are driven by one or multiple servo motors. The DC motor driven design allows for swimming at higher frequencies. The current design has been tested up to 5.5 Hz but can potentially reach much higher frequencies.